The present invention generally relates to electrical connecting devices.
There has been a proliferation of electrical tools and devices that are powered by batteries or can be plugged into common electrical outlets, with the latter capability requiring an AC to DC power conversion device. If a device is essentially DC powered, it may be connected directly to a battery or source of DC power or it may have a converter and be connected to a converter to an AC power outlet.
A common source of DC power is provided by motor vehicles through a cigarette lighter socket receptacle or similar auxiliary receptacle that is connected to the DC battery of the motor vehicle itself. If that type of source is used, a DC plug may be provided to connect a device directly to the socket to power for the device of interest. If it is to be powered by converted AC power, then a common two or three prong plug must be provided which is interconnected to an AC to DC converter for providing the DC voltage necessary to run the device. Many products currently commercially available include multiple devices that can be used for connecting to AC and DC sources, which requires the user to carry both kinds of connectors if they wish to use either type of power source.
It should be appreciated that a device that can be connected to such AC and DC sources should be designed in a manner whereby it is not possible to simultaneously connect both sources to a device for the obvious reason that internal circuitry could be destroyed or significantly damaged. Also, such a condition could present a safety hazard to a user. Plugs have been designed with adjustable configurations that can be used for different types of sockets that are found in different countries of the world, including configurations that are adapted to plug into standard electric AC outlets as well as DC cigarette lighter sockets contained in single housing. All of such known configurations are not designed to be completely foolproof in the sense that they could not be simultaneously connected to AC and DC sources.